Colourful Cottages

No.2 has yellow walls and red windows, and No.5 has a red door (clue 2). No.3 has green windows (clue 1), so (since each house has three colours, introduction) the adjoining houses (3) are No.4 with a green door and violet walls; and No.5 with orange walls and blue windows. The house with an orange door and indigo walls isn't No.3 (1), so the walls at No.3 are red. The windows at No.4 aren't violet (its walls are violet), so indigo. Thus the windows at No.1 are violet. The door at No.2 isn't yellow (its walls), so blue. By elimination, the door at No.3 is yellow.